the postion was 180 Degrees from the satellite. The za was
fixed at the stow position (8.8343 deg).

The data was piped to the ri a/d converters.

complex voltage samples were taken at a .5 usec sampling
rate (giving a 2 Mhz bw), 8 bit samples, and then written to
disc.

The 430 Mhz receiver was used (centered at 430 Mhz)

A 10 minute on, off cycle was used:

10 minutes pointing at the satellite

1 minute to move 3 beams from the satellite (in great circle
azimuth)

10 minutes pointing off the satellite.

29sep16 (AST): 327 receiver

yymmdd (AST = UTC - 4)

Tropical storm matthew (later
cat 5 hurricane matthew) was passing south of PR during this
observation. No local wind or rain, but there may have been
lightning far off in the distance (> 100 miles).

Observation sequence.

160930(UTC) (160929 AST): dome: 327 rcv, ch : 430
monitoring.

start time
hh:mm:ss
utc

on/off

object

mockfnum

mockrcvr

ri Filenums

rircvr

notes

00:50:53 to
01:01:00

on

gps
prn 18

000 -
007

327

001-002

430
ch

01:02:01 to
01;12:00

off

100 -
107

003-004

01:13:01 to
01:23:00

on

200-
207

005-006

01:24:00 to
01:34:00

off

300-
307

007-008

01:3500 to
01:54

on

400-
415

009-011

The satellite started to go out of the
beam between
01:58:00 and 01:59:00.

01:56:00

off

500-
507

012-013

we were more that 3 bms from the
satellite since it had set.

30sep16 (AST): 430 receiver

161001(UTC) (160930 AST): dome 430 rcvr, ch: 430
monitoring.

start time
hh:mm:ss
utc

on/off

object

mockfnum

mockrcvr

ri Filenums

rircvr

notes

00:46:00 to
00:56:00

on

gps
prn 18

000-
004

430

000-001

430

00:57:00 to
01:07:00

off

100-
104

002-003

01:08:00 to
01:18:00

on

200-
204

004-005

01:19:00 to
01:29:00

off

300-
304

006-007

01:30:00 to
01:50:

on

400-
408

008-010

Continue tracking satellite till it set

01:51:00 to
02:01

off

500-
504

011-012

satellite more than 3 bms away since it
had set.

Processing the data:

From the radiometer equation we have that:

deltaTsys/Tsys = 1/sqrt(channelBandwidth*time)

(Since we've added polarizations, the channel bandwidth has
been doubled..)

So computing the rms by channel and then normalizing to the
average channel value will give sigma values that should be
determined by the bandwidth and integration time.. if the signal
is noise like.. Any intermittent rfi (narrow channel frequeny
broadcasts) will increase the rms values in these channels..

broad band bursts from the satellite that lasts for 10's of
usecs will not affect this (since they are too short in
time).

PolA and polB were added together in the mock spectrometer,
before outputting the spectra.

Satellite beam:

each row of data (1 sec 430, .8 sec 327) was processed
separately:

dome 327: 40325 19.2 usec spectra /rec

dome 430: 52080 19.2 usec spectra/rec

compute rms/mean for each channel (over the 49325 ir
52080 spectra)

do a linear fit to the rms over the 128 or 256 freq
channels (excluding the edge channels where the analog/digital
filter) response fell off.

Create a freq channel mask that includes all freq channels
whose fit is within 3 sigma of the fit.

This mask will be used to compute the total power for each
19.2 usec spectra .. for this 1 sec of data.

for each of the 19.2usec spectra in the row () compute the
total power using the above row

output the data, and record which frequency channels were
used for this row.

repeat the above for each file of the scan

and continue for each scan of the day.

There will be 1 output file of floating point total power data
(sampled at 19.2 usecs) for each scan.

repeat the above for each day of data taking.

RFI BEAM:

this was 2 Mhz of complex voltage samples, centered at 430
Mhz.

all of the files comprising a 10min scan ( 8bit complex
voltages) was read in.

the mean was subtracted from the i, q channels (to get rid of
DC offsets)

the power was then computed for each .5 usec sample , and then
averaged to 10 usecs.

the mean and rms was then computed for the entire data set.

the output values were the tpOut[i]= (tpAvg[i] - mean)/rms

Comparing the two beams.

This is used when the on source an rfi beams are both 430
Mhz...

If we find a large sigma in the on source beam, we should
check the same time (and maybe 10 usecs on each side) to see
if there is a corresponding large sigma in the rfi beam..

If this is true, then the sigma in the on source beam is not
from the satellite.

Passing this test does not guarantee that the on source
large sigma is from the satellite..

the rfi bandwidth is only 2 Mhz.. there could be some
frequency channels outside this 2 mhz that has terrestrial
rfi.

broad band interference (say lightning) may appear in
both the satellite beam (at 327 Mhz) and the rfi beam at 430
Mhz.

Decide which broad band spikes to keep.

The satellite beam total power array was converted to sigmas.

sigSat[i]=(tpSat[i]- mean(tpSat))/rms(tpSat)

The rfi beam was already in sigmas

to be a valid broad band spike, the point had to meet:

the sigSat[i] had to be larger than the sigma
threshold (say 5 sigma)

the sigRfi[j] had to be less then the sigma threshold

For every sigSat[i] point, 3 points were checked in the
sigRfi[j] array (the one closest, 1 above, and 1below in
time)

If any of the 3 points in the sigRfi array were > than
the sigma threshold, then the sigSat[i] point was ignored.

The satellite spikes should be narrow in time .. say up to
100 usecs..??

Exporting files:

Each days data are stored under a separate
subdirectory (the directory names are the AST dates when data was
taken):
20160929,20160930

A scan is a contiguous set of data.

For each scan:

there is are two data sets:

there is a data set from the gregorian dome, mock
spectrometer

this is the beam that pointed at or close to the
satellite

the files start with mtp_ (mock Total Power)

There is a data set from the carriage house, ri a/d
interface

This is the beam that pointed 180 degrees from the
satellite (rfi beam)

the files start with rtp_

Each data set has:

file of total power data (4 byte floating point, little
endian)

Equally spaced in time

ends with .dat

an ascii header file that has some info on the scan

Filenames:

mtp_yyyymmdd_hhmmss.dat / .hdr

The date, time is the utc start time for the data in the
file

rtp_yyyymmdd_hhmmss.dat/hdr

The date, time is the utc start time for the data in the
file

Note: the mtp and rtp files do not necessarily
start at the same second